Timepiece Escapement with Semi-Direct Pulse and Segmented Teeth

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Solution Overview

Problem

The existing timepiece escapement with semi-direct impulse is sensitive to shocks and variations in orientation due to unbalanced rocker, which increases energy consumption when attempts are made to balance it.

Innovation Solution

The escapement design incorporates an escapement wheel with alternating short and long teeth, where short teeth exclusively interact with the entry rest surface and long teeth with both the exit rest and impulse surfaces, reducing rocker unbalance and sensitivity to shocks, and includes a self-starting tooth for automatic restart.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the rocker is balanced by adding protrusions, then the balance of the rocker is improved, but the inertia of the rocker increases and energy consumption increases

Engineering Contradiction:
Improverocker balanceVSAvoidenergy consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The escapement wheel teeth are segmented into three distinct types (first teeth for entry locking, second teeth for exit locking, third teeth for impulse transmission). This segmentation allows each tooth type to perform a specific function, enabling the rocker to achieve balance through the distributed mass of differently positioned teeth rather than adding concentrated protrusions, thus avoiding excessive inertia increase

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different teeth on the escapement wheel are given different local qualities - varying heights and positions - to optimize their specific functions. The first teeth are positioned for entry locking, second teeth for exit locking, and third teeth for impulse transmission. This local differentiation allows the rocker to be balanced through the strategic distribution of tooth masses rather than uniform additions

Inventive Principle:
Principle #3Local quality

2Reliability

If the rocker is balanced by adding protrusions, then the sensitivity to shocks and orientation variations is reduced, but the inertia of the rocker increases

Engineering Contradiction:
Improvesensitivity to shocks and orientationVSAvoidrocker inertia
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The escapement wheel teeth are segmented into three distinct types (first teeth for entry locking, second teeth for exit locking, third teeth for impulse transmission). This segmentation allows each tooth type to perform a specific function, enabling the rocker to achieve balance through the distributed mass of differently positioned teeth rather than adding concentrated protrusions, thus avoiding excessive inertia increase

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The escapement wheel features asymmetric tooth design with three different tooth types having different heights and angular positions. This asymmetry is strategically designed to balance the rocker while maintaining specific functional requirements for locking and impulse transmission, achieving reliability without symmetric protrusion additions that would increase inertia

Inventive Principle:
Principle #4Asymmetry

3Volume of moving object

If the angle between entry and exit rest positions is made smaller, then the escapement becomes more compact, but the rocker unbalance increases

Engineering Contradiction:
Improveescapement sizeVSAvoidrocker balance
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

Different teeth on the escapement wheel are given different local qualities - varying heights and positions - to optimize their specific functions. The first teeth are positioned for entry locking, second teeth for exit locking, and third teeth for impulse transmission. This local differentiation allows the rocker to be balanced through the strategic distribution of tooth masses rather than uniform additions

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The escapement wheel teeth are differentiated not only in angular position but also in the radial dimension (tooth height). The first, second, and third teeth have different heights extending radially from the wheel perimeter. This addition of radial dimension provides extra degrees of freedom for balancing the rocker while maintaining a compact angular footprint

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3982203B1Timepiece escapement with semi-direct pulse
Publication Date: 2022.12.14 PATEK PHILIPPE SA
  • EP3982203B1 patent drawingFigure 1~2
  • EP3982203B1 patent drawingFigure 3~4
  • EP3982203B1 patent drawingFigure 5~6

AI summary

The watch escapement according to the invention comprises an escape wheel (12), a rocker arm (14), and a balance wheel plate (16). The balance wheel plate (16) includes a pin (26) and an impulse tooth (28). The rocker arm (14) includes a fork (20), a first resting surface (30), a second resting surface (32), and an impulse surface (34).The escapement is arranged so that, when the balance wheel (16) rotates in a first direction (S1), the first resting surface (30) locks the escape wheel (12) in an entry rest position and then releases it under the action of the pin (26) cooperating with the fork (20) so that the escape wheel (12) comes into contact with the impulse tooth (28) to communicate an impulse to the balance wheel (16), and when the balance wheel (16) rotates in the direction (S2) opposite to the first direction (S1), the second resting surface (32) locks the escape wheel (12) in an exit rest position and then releases it under the action of the pin (26) cooperating with the fork (20) so that the escape wheel (12) comes into contact with the impulse surface (34) to communicate an impulse to the balance wheel (16) via the rocker (14).The angle (a) between the input and output rest positions is smaller than the angle (β) between the input rest position and the axis (B) of the rocker (14), these angles (α, β) being viewed from the axis (A) of the escape wheel (12). The escape wheel (12) comprises short teeth (36) and long teeth (38). The short teeth (36) are designed to cooperate exclusively with the first resting surface (30). The long teeth (38) are designed to cooperate with the second resting surface (32), the impulse surface (34), and the impulse tooth (28).